Method and heat-treating machine for material in strip form



y 1959 0. E. HEDBERG ET AL 3,444,289

METHOD AND HEAT-TREATING MACHINE FOR MATERIAL IN STRIP FORM Filed March 25, 1966 United States Patent 3,444,289 METHOD AND HEAT-TREATING MACHINE FOR MATERIAL IN STRIP FORM Oscar Emanuel Hedberg, Leif Erik Roland Soderberg, and

Johan Eric Hayden Westberg, Lidingo, Sweden, assignors to AGA Aktiebolag, Lidingo, Sweden, a corporation of Sweden Filed Mar. 23, 1966, Ser. No. 536,892 Claims priority, application Sweden, Apr. 29, 1965, 5,637/ 65 Int. Cl. 1329c 25/00 US. Cl. 264347 Claims ABSTRACT OF THE DISCLOSURE In a method of vulcanizing material in strip form, the material is Wound onto a main drum together with a separation strip, the coil or roll being terminated with a number of free outer layers of separation strip without any interposed material. The material is heated to the predetermined vulcanizing temperature, and the drum is rotated by pulling a number of the free outer layers of the separation strip off the main drum under tension while the material is in this heated condition, while simultaneously applying pressure to the material on the drum by at least one pressure roller bearing against the windings of the drum. Preferably a braking force is applied to the main drum to resist the rotation thereof and place the unwinding separation strip under additional tension. The force created by tensioning the unwinding strip to rotate the drum tends to be uniform during the entire vulcanizing period, and the movement of the main drum is steady. Preferably the unwinding is effected in a vulcanizing machine having a separate roll for drawing the separating strip from the main drum.

This invention relates to a machine and a method for effecting heat treatment, such as vulcanization, of a material in strip form, the material consisting of rubbercoated fabric or a rubber material in strip form.

In vulcanizing such strip material it is customary that the material be wound together with a separation strip on a drum of relatively large diameter, either in a separate winding machine or in the heat treating or vulcanizing machine proper. The separation strip preferably is electrically conductive so that it can be heated together with the material to be vulcanized to the vulcanizing temperature by connecting the separating strip to a current source and causing a current of suitable strength to pass through it, thereby imparting heat to the separation Strip as well as to the material to be vulcanized. In the vulcanizing machine the drum with the strip material and the separation strip wound thereon is rotated at the same time that the whole unit is subjected to pressure from one or more pressure rollers, and current is applied to the separation strip for heating the same.

The instant invention relates more particularly to an advantageous development of a vulcanizing machine of this type and a vulcanizing method of this type, and is characterized in that the separation strip or an extension thereof is of such length that when it is wound on the drum the coil is terminated by a number of turns of the separation strip without any interposed material to be vulcanized, the drum being adapted to be rotated by pulling a number of the free turns thus formed off the drum, preferably by winding them up on a rotating auxiliary drum. The invention also relates to an improved machine which facilitates practice of the new and improved method.

Accordingly, it is an object of this invention to provide a new and improved machine and a new and improved method for use in the heat treatment of vulcanizable material in strip form.

Other and further objects, advantages, and features of the invention will be apparent to those skilled in the art and armed with an understanding of the method and of a preferred embodiment of the new and improved machine.

We have set forth in the appended claims those novel features which we consider characteristic of our new machine and method, but the invention itself will be best understood by those skilled in the art from the following description of preferred embodiments thereof, taken with reference to the accompanying drawing wherein:

FIGURE 1 is a schematic section view of a preferred embodiment of a new and improved machine for practicing the method of the invention; and

FIGURES 2 and 3 are schematic side elevation views taken from opposite sides of the machine of FIGURE 1.

Referring to the drawing, a frame 1 supports a main drum 2 by means of an axle 3, the axle 3 being journaled for rotation in the frame 1 so as to be substantially freely movable vertically, a suitable journal arrangement being to rotatably embrace the axle 3 between two upright surfaces. The drum assembly is supported vertically by a rotatable supporting cylinder 4 which is journaled in the frame 1 beneath the main drum 2 by fixed bearings 5. Both the main drum 2 and the supporting cylinder 4 are enclosed in a housing 6 provided with heating devices 7 such as electric or steam coils, and also with a fan 8 for maintaining a uniform temperature throughout the housing. The heating devices 7 together with the fan 8 create inside the housing 6 a temperature approximately ''corresponding to the vulcanizing temperature of the material which is wound on the main drum 2, the vulcanizing temperature of the material being obtained by the heating of the separation strip.

The material to be heat treated or vulcanized is first wound up on the main drum 2 together with a preferably electrically conductive separation strip to form a layer 9 composed of a plurality of plies. The length of the separation strip is selected so as to make the outer turns of this multiple layer 9 exclusively of the separation strip, that is, the length of the separation strip is greater than that of the vulcanizable strip material by an amount sufficient to provide several turns of the separation strip after the vulcanizable strip material has been completely wound onto the main drum. The free end 10 of the separation strip runs over a pulley cylinder 11 to an auxiliary drum 12, to which the free end of the separation strip is joined mechanically as well as electrically. The other end of the separation strip is joined in a similar manner to the main drum 2. Electric current of suitable amperage can thus be made to flow through the separation strip by connecting the main drum 2 and the auxiliary drum 12 to a current source. This preferably is accomplished by means of coiled copper bands 13 and 14 having their inner ends connected to the axle of a respective drum, the number of turns and the length of the copper bands being such that with the outer ends of the bands fixed, the inner ends can make at least as many revolutions as the main drum 2 or the auxiliary drum 12. With this arrangement no brushes or other current transfer means with their attendant tendency to sparking are required.

The auxiliary drum 12 is driven by a motor 15 via a reduction gearing 16, the motor and gearing being proportioned so as to turn the auxiliary drum 12 very slowly at a rate of the order of a few revolutions per hour, there being obtained at the same time a high torque at the auxiliary drum 12. The main drum 2 is connected with a breaking device 17 which creates a braking effect on the drum 2 of suflicient force to create a tension of suitable magnitude in the separation strip when the latter is wound onto the auxiliary drum 12 from the main drum 2.

During the vulcanizing process, the main drum 2 with the material and the separation strip coiled thereon is thus rotated very slowly, and the material is exposed at the same time to a strong tensioning force created by the pull exerted by the auxiliary drum 12 at the same time that the braking action is produced by the braking de- 'vice 17. Simultaneously with this rotation and tensioning, the material is exposed to kneading action produced by the cylinder 4. The pressure between the drum 2 with the wound material 9 and the cylinder is determined by three factors. First, it depends upon the weight of the main drum with the material and separation strip coiled thereon; secondly, it is a function of the pulling force exerted by the auxiliary drum; and thirdly, it is a function of the braking moment of the braking device 17.

The length of the free end of the separation strip exceeding the length of the vulcanizable material strip is selected in view of the desired vulcanizing time and the rate of rotation of the drum 2 in such a way that only a portion, preferably about one half, of the outer free turns of the separation strip are wound off during the vulcanizing time onto the auxiliary drum 12. If, for example, the free end of the separation strip is assumed to have such a length that the outer portion of the coil is formed by twelve turns of the separation strip alone, the total wind-off time may be selected so that at the end thereof there remain six free turns of the separation strip wound on the drum 2, which contribute to maintain the desired strong pull on the material.

The braking device 17 may be of any convenient known construction, the only essential factor being that it should create sufficient braking force to set up the required tension in the separating strip. The braking force preferably is transferred to the frame via a linkage 18, 19 attached to the frame on the opposite side of the axle of the drum 2 relative to the strip leaving the main drum. This tends to reduce the load on the journaling of axle 3 of drum 2 and makes for a more symmetrical load on the supporting cylinder 4. The link 18 may be provided with a counterweight 20 serving to counterbalance the weight of the braking device 17 when the main drum 2 is being exchanged. Since the particular form of braking device forms no part of the instant invention, and since numerous suitable constructions will be readily apparent to persons skilled in the art, the braking device is shown only schematically in the drawings.

The embodiment shown in the drawing includes only one supporting cylinder 4 for creating during rotation of the drum 2 a kneading effect on the material to be treated. It is of course possible to provide additional supporting cylinders or kneading cylinders, the supporting cylinders being preferably symmetrically located and the additional kneading cylinders being evently distributed around the circumference of the principal drum with the material wound thereon. These additional cylinders may be pressed against the principal drum by heavy springs.

The separating strip need not, of course, be of the same material throughout its length, but rather it is within the scope of the invention to provide the separating strip with an extension 10 of other material to be connected with the auxiliary drum 12. Since the free extended end of the separating strip does not contact the vulcanizable strip material, it is necessary only that it be electrically conducting or that it have electrical conductors incorporated therein.

We claim:

1. A method of vulcanizing material in strip form, comprising winding the material onto a main drum together with a separation strip and terminating the material short of the end of the separation strip so as to complete the winding with a number of free outer layers of separation strip without any interposed material, heating the material to the predetermined vulcanizing temperature, rotating the main drum by pulling a number of the free outer layers of the separation strip off the main drum under tension while the material is in said heated condition and simultaneously applying radially inward pressure to the material on the drum during the rotation of the drum by at least one pressure roller bearing against the windings on the drum.

2. A method as set forth in claim 1 wherein said rotation is accomplished by winding said free outer layers of the separation strip onto an auxiliary drum from the main drum.

3. A method as set forth in claim 2 wherein a braking force is applied to said main drum to resist the rotation thereof and place the unwinding separation strip under additional tension.

4. A method as set forth in claim 3 wherein the radially inward pressure is applied by at least partially supporting the main drum vertically by a roller which bears against the wound material and separation strip.

5. A method as set forth in claim 2 wherein the separating strip is electrically conducting, and the heating of the material is effected at least partially by applying an electric current to the separating strip.

6. A method as set forth in claim 5 wherein the separating strip at its ends is connected electrically to the main drum and the auxiliary drum, respectively, and wherein the electric current is applied through one of the drums, through the separating strip, and to the other drum.

7. In a heat treating machine for vulcanization of a material in strip form, a main drum for supporting the strip material and a separation strip wound thereon so as to have a number of outer wound layers formed solely by the separation strip 'without any interposed strip material, frame means mounting said main drum for rotation about its longitudinal axis, at least one rotatable pressure cylinder for bearing against the main drum and any windings thereon during rotation of the main drum, a rotatably mounted auxiliary drum substantially parallel to and spaced from said main drum for receiving the free end of the separating strip from the main drum so as to effect unwinding thereof, means for rotating said auxiliary drum about its longitudinal axis, brake means for resisting rotation of the main drum, and means for heating any material wound on the main drum, whereby the free end of the separating strip can be connected to the auxiliary drum from the main drum and the main drum rotated by winding the separating strip onto the auxiliary drum while the strip material is subjected to heat, a compressive action from the tension in the separating strip and a kneading action by said pressure cylinder, and the time and amount of treatment can be varied by varying the number of free outer turns of the separation strip.

8. Apparatus as set forth in claim 7 wherein the brake means is an external brake connected to said frame means on the opposite side of the axis of the main drum relative to the point where the separation strip leaves the main drum to be wound onto the auxiliary drum.

9. Apparatus as set forth in claim 7 wherein said means mounting said main drum permits said main drum to move vertically, and wherein the main drum is supported vertically at least partially by at least one rotatable pressure roller upon which the main drum and any windings thereon rest.

10. Apparatus as set forth in claim 7 wherein the separating strip is electrically conducting, and further comprising coiled electrical connectors mounted on the axes of the main drum and the auxiliary drum, the inner end of each coiled connector being fixed to a respective axis for rotation therewith and the outer ends being stationarily fixed for connection to an electric circuit, whereby current may be applied to one coiled connector to pass therethrough, through the corresponding drum, through the separating strip, through the other drum, and through the 5 6 other coiled connector, the number of turns and the length 2,054,000 9/ 1936 Neerbye 264 -347 XR of each coiled connector being such as to permit the 3,271,504 9/1966 Bergstrom et a1. 264-347 inner end to make as many revolutions as its corresponding drum. PHILIP E. ANDERSON, Primary Examiner.

References Cited 5 US. Cl. X.R.

UNITED STATES PATENTS 18-6; 264319 1,237,554 8/1918 Price 264347 XR 1,497,112 6/1924 Matthew 264-347 XR 

